Magneto-optic effects such as Faraday Effect are popularly used in measurement of the electrical current or magnetic field. Magneto-optic glass, magneto-optic crystal or fiber etc. is usually used for achieving Faraday Effect.
As shown in FIG. 1, a fiber magneto-optic detection system in the prior art is shown comprising a power supply and signal processing module 400, a magneto-optic probe 100 and a conductive fiber device 200. The power supply and signal processing module 400 emits laser light which is transmitted to the magneto-optic probe 100 through the fiber device 200. The magneto-optic probe is designed to sense the magnetic field of the environment in which the magneto-optic probe 100 is located, based on a certain optical principle such as Faraday Effect, and convert the magnetic field signal into optical signal. The optical signal is carried by the laser light and transmitted back to the power supply and signal processing module 400 via the fiber device 200. The power supply and signal processing module 400 performs data processing based on the optical signal received, so as to obtain information on the magnetic field of the measurement point.
During the measurement process shown in FIG. 1, various materials and optical structures may be affected by the environmental factors such as temperature and stress or the intensity of the magnetic field to be measured. These affections cause the inaccuracy in measurement, such that the precision of measurement may not meet the application requirement.
The inventor recognizes in developing the invention that various materials used in the magneto-optic measurement are always affected by the environmental factors such as temperature, stress or the intensity of the magnetic field to be measured, which will cause improper measurement. Especially, the inventor recognizes that when some material such as garnet crystal is used as a magneto-optic medium to measure the magnetic field, the microcosmic structure of magnetic domains inside the garnet crystal changes unpredictably when the crystal is subjected to a certain intensity of direct-current or alternating magnetic field, which affects the optical characteristics and leads to uncertain measurement results. In the art, there is no reasonable solution for resolving such problems.